Currently, JCR system properties are only mentioned in two places:

• On the JCR browser app docu page - noting that they are hidden by default but they can be displayed via a dropdown option
• On the JCR data source page - here we have the includeProperties property

MAGNOLIA-9202 addresses the jcr:title property. When that's implemented it would be good to create a section about JCR system properties somewhere and include details for the jcr:title updates in MAGNOLIA-9202.